The Arabic letter ث is named ثاءṯāʾ. It is written is several ways depending in its position in the word:

Position in word:

Isolated

Final

Medial

Initial

Glyph form:

ث‎

ـث‎

ـثـ‎

ثـ‎

In contemporary spoken Arabic, pronunciation of ṯāʾ as [θ] is found in the Gulf, Iraqi, and Tunisian dialects and in highly educated pronunciations of Modern Standard and Classical Arabic. Pronunciation of the letter varies between and within the various varieties of Arabic: while it is consistently pronounced as the voiceless dental plosive[t] in Maghrebi Arabic, in the Arabic varieties of the Mashriq (in the broad sense, including Egyptian, Sudanese and Levantine) and Hejazi Arabic, it can be pronounced as either [t] or as the sibilantvoiceless alveolar fricative[s]. Depending on the word in question, words pronounced as [s] are generally more technical or "sophisticated." Regardless of these regional differences, the pattern of the speaker's variety of Arabic frequently intrudes into otherwise Modern Standard speech; this is widely accepted, and is the norm when speaking the mesolect known alternately as lugha wusṭā ("middling/compromise language") or ʿAmmiyyat/Dārijat al-Muṯaqqafīn ("Educated/Cultured Colloquial") used in the informal speech of educated Arabs of different countries.

When representing this sound in transliteration of Arabic into Hebrew, it is written as ת׳.